In recent years, a memory card in which, for example, a semiconductor memory such as a NAND flash memory is used has been used for purposes of recording consecutively shot still images and a high-resolution motion image. Then, these uses to read or write a lot of information in a short time, i.e., increase data transfer speed.
In a conventional SD™ memory card (hereinafter, described as SD memory card), the data transfer speed is as high as about 20 MB/sec. Then, aside from in a normal operation mode (normal mode), even in an operation mode (high-speed mode) in which information can be read and written at a higher speed than the normal mode, so that high-speed data transfer can be performed while maintaining compatibility with a normal host device.
In the case of enabling switching of the operation mode, if functions of all of pins are changed in each mode, a load on a controller that controls the semiconductor memory increases, which prevents increase in data transfer speed. Therefore, pins for high-speed mode are provided other than pins for normal mode. On the other hand, if pins are newly provided corresponding to all of signals used in the high speed mode similarly to a two-row arrangement such as one employed in the MMC (Multi Media Card) standard, this increases constraints on a wiring layout of a circuit substrate on which the semiconductor memory is mounted (see Japanese Patent Application Laid-open No. 2005-84935)